Exam 1: CNS Flashcards
(90 cards)
PGC’s are visible in the yolk sac during which weeks of gestation?
4-6
When do PGC’s become gonocytes?
When they reach the gonads
When PCG’s reach the gonads and become gonocytes, which supporting cells are secreted?
Sertoli cells (male) granulosa cells (female)
What is the era of spermatogenesis?
Puberty to death
What regulates spermatogenesis?
Testosterone and androgen receptors
Does spermatogenesis create spermatozoa through mitosis or meiosis?
Meiosis
How long does spermatogenesis take?
2 months
The 2nd meiotic division occurs…
hours before ovulation occurs
Does a teratogen affect all the body systems at the same time?
No, not all body systems develop at the same time so a teratogen can affect 1 without affecting the others
What happens during week 1?
Fertilization and zygote formation
What happens during week 2?
Implantation, bilaminar disc forms, placenta forms, amniotic fluid forms
What happens during week 3?
Gastrulation, neural crest formations, and embryonic folding
Where does implantation usually occur?
Posterior uterus wall
Important for blood cell, germ cell, and gut development?
Yolk sac
Transfers nutrients during the early stages of development?
Yolk sac
How are chorionic villi formed?
By extension of the cytotrophoblast and then grow into the syncytiotrophoblast
Polyhydramnios
Too much amniotic fluid
Oligohydramnios
Too little amniotic fluid
What is special about the buccopharyngeal (oropharyngeal) and cloacal membranes?
They do not trilaminate. They remain bilaminar
The primitive streak is formed by the proliferation & movement of which cells to the median plane?
Epiblast
Cells that travel through the primitive streak first & displace the hypoblast?
Endoderm
Which structure induces the overlying ectoderm to form the central nervous system
Notochord
When does the primitive streak disappear?
At the end of week 4
Neural crest cells arise directly from:
Dorsal part of the neural tube
